baltemission<-NEI[NEI$fips=="24510" & NEI$type=="ON-ROAD", ]
losaemission<-NEI[NEI$fips=="06037" & NEI$type=="ON-ROAD", ]
baltemission$County<-"Baltimore City, MD"
losaemission$County<-"Los Angeles County, CA"
bothemissions <- rbind(baltemission,losaemission)
g<-ggplot(bothemissions,aes(x=factor(year),y=Emissions,fill=year,label=round(Emissions,2)))
g+geom_bar(stat="identity")+facet_grid(.~County,)+xlab("Years")+
ylab(expression("PM"[2.5]*"Emissions from motor vehicles"))+
geom_label(aes(fill = year),colour = "white", fontface = "bold")
May I ask why did it appear seperated? Thank you.