Issue with Separating a Single Plot from a Figure of Plots using facet_wrap()

I have successfully created multiple bar charts in one figure that illustrates ozone concentrations for various cities in North Carolina. Now, I want to separate certain plots from this figure so only a single plot is shown. For example, rather than the output being the figure with each plot for each city, I'd rather have the output be the single bar plot for Asheville or Cullowhee. I was told facet_wrap() can help with this but have had no luck. Any help would be much appreciated!

### Libraries Used
library(httr)
library(jsonlite)
library(ggplot2)
library(dplyr)

### Sample Data Set
data.frame(stringsAsFactors=FALSE,
              data_cbsa = c("Asheville, NC", "Asheville, NC", "Asheville, NC",
                            "Asheville, NC", "Asheville, NC", "Asheville, NC",
                            "Asheville, NC", "Asheville, NC", "Asheville, NC",
                            "Asheville, NC", "Asheville, NC", "Asheville, NC",
                            "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia,
                            NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC",
                            "Charlotte-Concord-Gastonia, NC-SC", "Cullowhee, NC", "Cullowhee, NC",
                            "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                            "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                            "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                            "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC", "Fayetteville,
                            NC", "Fayetteville, NC", "Fayetteville, NC",
                            "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC",
                            "Fayetteville, NC", "Fayetteville, NC", "Fayetteville,
                            NC", "Fayetteville, NC", "Fayetteville, NC",
                            "Fayetteville, NC", "Greensboro-High Point, NC",
                            "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                            "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                            "Greensboro-High Point, NC", "Greensboro-High Point,
                            NC", "Greensboro-High Point, NC",
                            "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                            "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                            "Greenville, NC", "Greenville, NC", "Greenville, NC",
                            "Greenville, NC", "Greenville, NC", "Greenville, NC",
                            "Greenville, NC", "Greenville, NC", "Greenville, NC",
                            "Greenville, NC", "Greenville, NC", "Greenville, NC",
                            "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton,
                            NC", "Hickory-Lenoir-Morganton, NC",
                            "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                            "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton,
                            NC", "Hickory-Lenoir-Morganton, NC",
                            "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                            "Hickory-Lenoir-Morganton, NC",
                            "Hickory-Lenoir-Morganton, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                            "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston,
                            NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                            "Kinston, NC", "Kinston, NC", "Morehead City, NC",
                            "Morehead City, NC", "Morehead City, NC", "Morehead City,
                            NC", "Morehead City, NC", "Morehead City, NC",
                            "Morehead City, NC", "Morehead City, NC", "Morehead City,
                            NC", "Morehead City, NC", "Morehead City, NC",
                            "Morehead City, NC", "Oxford, NC", "Oxford, NC", "Oxford,
                            NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                            "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                            "Oxford, NC", "Oxford, NC", "Raleigh, NC", "Raleigh, NC",
                            "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                            "Raleigh, NC", "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                            "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                            "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                            "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                            "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount,
                            NC", "Rocky Mount, NC", "Rocky Mount, NC",
                            "Rocky Mount, NC", "Sanford, NC", "Sanford, NC", "Sanford, NC",
                            "Sanford, NC", "Sanford, NC", "Wilmington, NC",
                            "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                            "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                            "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                            "Wilmington, NC", "Wilmington, NC", "Winston-Salem,
                            NC", "Winston-Salem, NC", "Winston-Salem, NC",
                            "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC",
                            "Winston-Salem, NC", "Winston-Salem, NC",
                            "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC"),
              data_year = c(2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                            2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                            2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                            2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
                            2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                            2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011,
                            2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                            2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                            2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
                            2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                            2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                            2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                            2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                            2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                            2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,
                            2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015,
                            2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                            2013, 2014, 2015, 2016, 2017, 2018, 2014, 2015, 2016,
                            2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                            2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                            2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017),
   highest_4th_max_cbsa = c(0.077, 0.08, 0.066, 0.074, 0.067, 0.07, 0.064,
                            0.067, 0.066, 0.067, 0.063, 0.065, 0.096, 0.093,
                            0.073, 0.082, 0.088, 0.085, 0.067, 0.068, 0.073, 0.074,
                            0.068, 0.07, 0.08, 0.063, 0.069, 0.068, 0.069,
                            0.067, 0.068, 0.065, 0.069, 0.064, 0.065, 0.08, 0.078,
                            0.066, 0.074, 0.072, 0.076, 0.062, 0.065, 0.061, 0.063,
                            0.061, 0.063, 0.082, 0.075, 0.068, 0.073, 0.076,
                            0.069, 0.062, 0.066, 0.062, 0.064, 0.063, 0.064, 0.086,
                            0.084, 0.072, 0.076, 0.076, 0.078, 0.062, 0.065,
                            0.066, 0.068, 0.065, 0.067, 0.079, 0.077, 0.066, 0.069,
                            0.074, 0.071, 0.063, 0.063, 0.06, 0.065, 0.061, 0.066,
                            0.081, 0.076, 0.064, 0.071, 0.067, 0.067, 0.063,
                            0.064, 0.065, 0.066, 0.063, 0.065, 0.077, 0.074, 0.064,
                            0.069, 0.069, 0.069, 0.063, 0.065, 0.062, 0.063,
                            0.062, 0.064, 0.07, 0.059, 0.062, 0.065, 0.063, 0.058,
                            0.062, 0.062, 0.058, 0.06, 0.057, 0.06, 0.083, 0.081,
                            0.07, 0.074, 0.072, 0.072, 0.063, 0.065, 0.063, 0.065,
                            0.065, 0.065, 0.084, 0.078, 0.069, 0.074, 0.078,
                            0.075, 0.062, 0.064, 0.065, 0.069, 0.066, 0.063, 0.08,
                            0.075, 0.066, 0.072, 0.072, 0.071, 0.064, 0.062, 0.061,
                            0.064, 0.061, 0.062, 0.064, 0.06, 0.064, 0.059,
                            0.06, 0.071, 0.066, 0.06, 0.062, 0.064, 0.064, 0.064,
                            0.063, 0.057, 0.06, 0.057, 0.062, 0.085, 0.081, 0.068,
                            0.081, 0.076, 0.079, 0.066, 0.067, 0.07, 0.07, 0.066)
)

### Minimal Runnable Code 
ggplot(o3_cbsa_annual_2015_std_summary, 
       aes(x=data_year,y=highest_4th_max_cbsa)) + 
  geom_col(position = "dodge", fill = 'red') +
  facet_wrap(~data_cbsa, 'Asheville, NC')
Warning messages:
  1: Coercing `nrow` to be an integer. 
2: In sanitise_dim(nrow) : NAs introduced by coercion
3: `nrow` is missing or less than 1 and will be treated as NULL.

If you want only one plot, do you really need to use facet_wrap? You can make the plot based on a subset of the dataset. For example, run this:

o3_cbsa_annual_2015_std_summary <- data.frame(stringsAsFactors=FALSE,
                 data_cbsa = c("Asheville, NC", "Asheville, NC", "Asheville, NC",
                               "Asheville, NC", "Asheville, NC", "Asheville, NC",
                               "Asheville, NC", "Asheville, NC", "Asheville, NC",
                               "Asheville, NC", "Asheville, NC", "Asheville, NC",
                               "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC",
                               "Charlotte-Concord-Gastonia, NC-SC", "Cullowhee, NC", "Cullowhee, NC",
                               "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                               "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                               "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                               "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC", "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC",
                               "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC",
                               "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC",
                               "Fayetteville, NC", "Greensboro-High Point, NC",
                               "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                               "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                               "Greensboro-High Point, NC", "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                               "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                               "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                               "Greenville, NC", "Greenville, NC", "Greenville, NC",
                               "Greenville, NC", "Greenville, NC", "Greenville, NC",
                               "Greenville, NC", "Greenville, NC", "Greenville, NC",
                               "Greenville, NC", "Greenville, NC", "Greenville, NC",
                               "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                               "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                               "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                               "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                               "Hickory-Lenoir-Morganton, NC",
                               "Hickory-Lenoir-Morganton, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                               "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                               "Kinston, NC", "Kinston, NC", "Morehead City, NC",
                               "Morehead City, NC", "Morehead City, NC", "Morehead City, NC", "Morehead City, NC", "Morehead City, NC",
                               "Morehead City, NC", "Morehead City, NC", "Morehead City, NC", "Morehead City, NC", "Morehead City, NC",
                               "Morehead City, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                               "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                               "Oxford, NC", "Oxford, NC", "Raleigh, NC", "Raleigh, NC",
                               "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                               "Raleigh, NC", "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                               "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                               "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                               "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                               "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                               "Rocky Mount, NC", "Sanford, NC", "Sanford, NC", "Sanford, NC",
                               "Sanford, NC", "Sanford, NC", "Wilmington, NC",
                               "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                               "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                               "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                               "Wilmington, NC", "Wilmington, NC", "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC",
                               "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC",
                               "Winston-Salem, NC", "Winston-Salem, NC",
                               "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC"),
                 data_year = c(2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                               2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                               2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                               2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
                               2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                               2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011,
                               2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                               2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                               2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
                               2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                               2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                               2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                               2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                               2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                               2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,
                               2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015,
                               2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                               2013, 2014, 2015, 2016, 2017, 2018, 2014, 2015, 2016,
                               2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                               2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                               2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017),
                 highest_4th_max_cbsa = c(0.077, 0.08, 0.066, 0.074, 0.067, 0.07, 0.064,
                                          0.067, 0.066, 0.067, 0.063, 0.065, 0.096, 0.093,
                                          0.073, 0.082, 0.088, 0.085, 0.067, 0.068, 0.073, 0.074,
                                          0.068, 0.07, 0.08, 0.063, 0.069, 0.068, 0.069,
                                          0.067, 0.068, 0.065, 0.069, 0.064, 0.065, 0.08, 0.078,
                                          0.066, 0.074, 0.072, 0.076, 0.062, 0.065, 0.061, 0.063,
                                          0.061, 0.063, 0.082, 0.075, 0.068, 0.073, 0.076,
                                          0.069, 0.062, 0.066, 0.062, 0.064, 0.063, 0.064, 0.086,
                                          0.084, 0.072, 0.076, 0.076, 0.078, 0.062, 0.065,
                                          0.066, 0.068, 0.065, 0.067, 0.079, 0.077, 0.066, 0.069,
                                          0.074, 0.071, 0.063, 0.063, 0.06, 0.065, 0.061, 0.066,
                                          0.081, 0.076, 0.064, 0.071, 0.067, 0.067, 0.063,
                                          0.064, 0.065, 0.066, 0.063, 0.065, 0.077, 0.074, 0.064,
                                          0.069, 0.069, 0.069, 0.063, 0.065, 0.062, 0.063,
                                          0.062, 0.064, 0.07, 0.059, 0.062, 0.065, 0.063, 0.058,
                                          0.062, 0.062, 0.058, 0.06, 0.057, 0.06, 0.083, 0.081,
                                          0.07, 0.074, 0.072, 0.072, 0.063, 0.065, 0.063, 0.065,
                                          0.065, 0.065, 0.084, 0.078, 0.069, 0.074, 0.078,
                                          0.075, 0.062, 0.064, 0.065, 0.069, 0.066, 0.063, 0.08,
                                          0.075, 0.066, 0.072, 0.072, 0.071, 0.064, 0.062, 0.061,
                                          0.064, 0.061, 0.062, 0.064, 0.06, 0.064, 0.059,
                                          0.06, 0.071, 0.066, 0.06, 0.062, 0.064, 0.064, 0.064,
                                          0.063, 0.057, 0.06, 0.057, 0.062, 0.085, 0.081, 0.068,
                                          0.081, 0.076, 0.079, 0.066, 0.067, 0.07, 0.07, 0.066)
)

library(ggplot2)

ggplot(data = subset(x = o3_cbsa_annual_2015_std_summary,
                     data_cbsa == 'Asheville, NC'),
       mapping = aes(x = data_year,
                     y = highest_4th_max_cbsa)) +
  geom_col(fill = 'red')

Created on 2019-08-16 by the reprex package (v0.3.0)

For your future posts, please provide a smaller dataset sufficient enough to reproduce the problem. Also, please include the library calls.

facet_wrap() generates a "facet" (or subplot) for each level of a categorical variable, see this example.

### Libraries Used
library(ggplot2)
library(dplyr)

### Sample Data Set
o3_cbsa_annual_2015_std_summary <- data.frame(stringsAsFactors=FALSE,
           data_cbsa = c("Asheville, NC", "Asheville, NC", "Asheville, NC",
                         "Asheville, NC", "Asheville, NC", "Asheville, NC",
                         "Asheville, NC", "Asheville, NC", "Asheville, NC",
                         "Asheville, NC", "Asheville, NC", "Asheville, NC",
                         "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia,
                            NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC", "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC",
                         "Charlotte-Concord-Gastonia, NC-SC", "Cullowhee, NC", "Cullowhee, NC",
                         "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                         "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                         "Cullowhee, NC", "Cullowhee, NC", "Cullowhee, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC",
                         "Durham-Chapel Hill, NC", "Durham-Chapel Hill, NC", "Fayetteville,
                            NC", "Fayetteville, NC", "Fayetteville, NC",
                         "Fayetteville, NC", "Fayetteville, NC", "Fayetteville, NC",
                         "Fayetteville, NC", "Fayetteville, NC", "Fayetteville,
                            NC", "Fayetteville, NC", "Fayetteville, NC",
                         "Fayetteville, NC", "Greensboro-High Point, NC",
                         "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                         "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                         "Greensboro-High Point, NC", "Greensboro-High Point,
                            NC", "Greensboro-High Point, NC",
                         "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                         "Greensboro-High Point, NC", "Greensboro-High Point, NC",
                         "Greenville, NC", "Greenville, NC", "Greenville, NC",
                         "Greenville, NC", "Greenville, NC", "Greenville, NC",
                         "Greenville, NC", "Greenville, NC", "Greenville, NC",
                         "Greenville, NC", "Greenville, NC", "Greenville, NC",
                         "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton,
                            NC", "Hickory-Lenoir-Morganton, NC",
                         "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                         "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton,
                            NC", "Hickory-Lenoir-Morganton, NC",
                         "Hickory-Lenoir-Morganton, NC", "Hickory-Lenoir-Morganton, NC",
                         "Hickory-Lenoir-Morganton, NC",
                         "Hickory-Lenoir-Morganton, NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                         "Kinston, NC", "Kinston, NC", "Kinston, NC", "Kinston,
                            NC", "Kinston, NC", "Kinston, NC", "Kinston, NC",
                         "Kinston, NC", "Kinston, NC", "Morehead City, NC",
                         "Morehead City, NC", "Morehead City, NC", "Morehead City,
                            NC", "Morehead City, NC", "Morehead City, NC",
                         "Morehead City, NC", "Morehead City, NC", "Morehead City,
                            NC", "Morehead City, NC", "Morehead City, NC",
                         "Morehead City, NC", "Oxford, NC", "Oxford, NC", "Oxford,
                            NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                         "Oxford, NC", "Oxford, NC", "Oxford, NC", "Oxford, NC",
                         "Oxford, NC", "Oxford, NC", "Raleigh, NC", "Raleigh, NC",
                         "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                         "Raleigh, NC", "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                         "Raleigh, NC", "Raleigh, NC", "Raleigh, NC",
                         "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                         "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount, NC",
                         "Rocky Mount, NC", "Rocky Mount, NC", "Rocky Mount,
                            NC", "Rocky Mount, NC", "Rocky Mount, NC",
                         "Rocky Mount, NC", "Sanford, NC", "Sanford, NC", "Sanford, NC",
                         "Sanford, NC", "Sanford, NC", "Wilmington, NC",
                         "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                         "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                         "Wilmington, NC", "Wilmington, NC", "Wilmington, NC",
                         "Wilmington, NC", "Wilmington, NC", "Winston-Salem,
                            NC", "Winston-Salem, NC", "Winston-Salem, NC",
                         "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC",
                         "Winston-Salem, NC", "Winston-Salem, NC",
                         "Winston-Salem, NC", "Winston-Salem, NC", "Winston-Salem, NC"),
           data_year = c(2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                         2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                         2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                         2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017,
                         2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014,
                         2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011,
                         2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                         2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                         2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012, 2013,
                         2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009, 2010,
                         2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2007,
                         2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016,
                         2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                         2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                         2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018,
                         2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015,
                         2016, 2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                         2013, 2014, 2015, 2016, 2017, 2018, 2014, 2015, 2016,
                         2017, 2018, 2007, 2008, 2009, 2010, 2011, 2012,
                         2013, 2014, 2015, 2016, 2017, 2018, 2007, 2008, 2009,
                         2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017),
           highest_4th_max_cbsa = c(0.077, 0.08, 0.066, 0.074, 0.067, 0.07, 0.064,
                                    0.067, 0.066, 0.067, 0.063, 0.065, 0.096, 0.093,
                                    0.073, 0.082, 0.088, 0.085, 0.067, 0.068, 0.073, 0.074,
                                    0.068, 0.07, 0.08, 0.063, 0.069, 0.068, 0.069,
                                    0.067, 0.068, 0.065, 0.069, 0.064, 0.065, 0.08, 0.078,
                                    0.066, 0.074, 0.072, 0.076, 0.062, 0.065, 0.061, 0.063,
                                    0.061, 0.063, 0.082, 0.075, 0.068, 0.073, 0.076,
                                    0.069, 0.062, 0.066, 0.062, 0.064, 0.063, 0.064, 0.086,
                                    0.084, 0.072, 0.076, 0.076, 0.078, 0.062, 0.065,
                                    0.066, 0.068, 0.065, 0.067, 0.079, 0.077, 0.066, 0.069,
                                    0.074, 0.071, 0.063, 0.063, 0.06, 0.065, 0.061, 0.066,
                                    0.081, 0.076, 0.064, 0.071, 0.067, 0.067, 0.063,
                                    0.064, 0.065, 0.066, 0.063, 0.065, 0.077, 0.074, 0.064,
                                    0.069, 0.069, 0.069, 0.063, 0.065, 0.062, 0.063,
                                    0.062, 0.064, 0.07, 0.059, 0.062, 0.065, 0.063, 0.058,
                                    0.062, 0.062, 0.058, 0.06, 0.057, 0.06, 0.083, 0.081,
                                    0.07, 0.074, 0.072, 0.072, 0.063, 0.065, 0.063, 0.065,
                                    0.065, 0.065, 0.084, 0.078, 0.069, 0.074, 0.078,
                                    0.075, 0.062, 0.064, 0.065, 0.069, 0.066, 0.063, 0.08,
                                    0.075, 0.066, 0.072, 0.072, 0.071, 0.064, 0.062, 0.061,
                                    0.064, 0.061, 0.062, 0.064, 0.06, 0.064, 0.059,
                                    0.06, 0.071, 0.066, 0.06, 0.062, 0.064, 0.064, 0.064,
                                    0.063, 0.057, 0.06, 0.057, 0.062, 0.085, 0.081, 0.068,
                                    0.081, 0.076, 0.079, 0.066, 0.067, 0.07, 0.07, 0.066)
)

### Minimal Runnable Code 
o3_cbsa_annual_2015_std_summary %>% 
    filter(data_cbsa %in% c("Asheville, NC", "Cullowhee, NC")) %>% # Filter desired values.
    ggplot(aes(x = data_year, y = highest_4th_max_cbsa)) + 
    geom_col(position = "dodge", fill = 'red') +
    facet_wrap(~data_cbsa) # Generate sub plots for each level of the categorical variable.

Created on 2019-08-16 by the reprex package (v0.3.0.9000)

A line plot might work better here. For example:

library(tidyverse)

o3_cbsa_annual_2015_std_summary %>% 
  # Remove state abbreviations from metro area names
  mutate(data_cbsa = gsub(",.*", "", data_cbsa)) %>% 
  # Set metro area order from highest to lowest 2018 ozone levels
  arrange(desc(data_year), desc(highest_4th_max_cbsa)) %>% 
  mutate(data_cbsa = factor(data_cbsa, levels=unique(data_cbsa))) %>% 
  ggplot(aes(x=data_year,y=highest_4th_max_cbsa, colour=data_cbsa)) + 
    geom_hline(yintercept=0.070, linetype="11", colour="red") +
    geom_line() +
    expand_limits(y=0) +
    scale_y_continuous(expand=expand_scale(mult=c(0,0.02))) +
    scale_x_continuous(breaks=seq(2008,2020,2)) +
    theme_minimal() +
    scale_colour_viridis_d(end=0.9) +
    labs(y="4th max (ppm)",
         x="Year", 
         colour="Metro Area")

Or if that's too busy:

o3_cbsa_annual_2015_std_summary %>% 
  mutate(data_cbsa = gsub(",.*", "", data_cbsa)) %>% 
  ggplot(aes(x=data_year,y=highest_4th_max_cbsa)) + 
  geom_hline(yintercept=0.070, linetype="11", colour="red") +
    geom_line() +
    expand_limits(y=0) +
    scale_y_continuous(expand=expand_scale(mult=c(0,0.04))) +
    scale_x_continuous(breaks=seq(2008,2020,2)) +
    theme_bw() +
    theme(axis.text.x=element_text(angle=-90, vjust=0.5)) +
    labs(y="4th max (ppm)", x="Year") +
    facet_wrap(~data_cbsa)

Or you could go super-minimal:

library(ggthemes)

o3_cbsa_annual_2015_std_summary %>% 
  mutate(data_cbsa = gsub(",.*", "", data_cbsa)) %>% 
  arrange(desc(data_year), desc(highest_4th_max_cbsa)) %>% 
  mutate(data_cbsa = factor(data_cbsa, levels=unique(data_cbsa))) %>% 
  ggplot(aes(x=data_year,y=highest_4th_max_cbsa)) + 
    geom_text(data=. %>% group_by(data_cbsa) %>% slice(1), 
              aes(label=str_wrap(data_cbsa, 17)), 
              y=0.01, x=2012, size=2.8, family="serif", vjust=0) +
    geom_hline(yintercept=0.070, linetype="11", colour="red") +
    geom_hline(yintercept=0, size=0.3, colour="grey60") +
    geom_line() +
    expand_limits(y=0) +
    scale_y_continuous(expand=expand_scale(mult=c(0,0.02))) +
    scale_x_continuous(breaks=seq(2008,2020,4)) +
    theme_tufte() +
    theme(axis.text.x=element_text(angle=-90, vjust=0.5, size=rel(0.8)),
          axis.ticks.x=element_line(colour="grey50"),
          axis.title.x=element_blank(), 
          strip.text=element_blank()) +
    labs(y="4th max (ppm)") +
    facet_wrap(~data_cbsa, nrow=2)

And, of course, you can show subsets, as demonstrated in the other responses.