identical. Since CO and HC are largely produced by
transportation, the 1968 patterns still apply.
The first
set of maps (Figs. 6-3 to 6-6) relates variations in carbon
monoxide to the four socioeconomic characteristics. Beginning with
poverty and CO (Fig. 6-3), the most highly polluted areas (10
mg/m3 and above, which is higher than the federal
standard) are almost entirely in poverty areas. A few other
vulnerable places include some affluent or middle income households
on Capitol Hill and Embassy Row.
Figure 6-4,
which matches CO concentration and occupations, shows that most of
the highly polluted zones have low proportions of professional and
managerial workers. Since low proportions in these categories is
much more widespread than poverty, many such areas exist outside
the isopleth pattern altogether. However, areas with a high
proportion of professional and managerial workers are usually in
low pollution zones.
Figure 6-5,
which charts rent levels and CO, tells the same story. Here, most
high rent zones are within the outermost isopleth and the area of
highest CO pollution is almost entirely low rent. Figure 6-6
demonstrates it is highly probable that areas 75 percent or more
black will have high CO pollution, although the correspondence here
is not as close.
This
introduces the idea of probability of living in a high
pollution area—a very important concept to keep in mind with
this and other sets of maps. Take the map of CO and poverty. It
most emphatically does not mean that everyone who is poor
lives in a high pollution zone and everyone who is well off lives
in a low CO area. Many representatives and senators live on Capitol
Hill, in the most polluted part of the city. They breathe the same
air as the poor people who live there. Thus, areas reaching or
exceeding federal pollution standards in Washington contain both
rich and poor—and middle class, for that matter. The point is
that, taking the entire population of rich and the entire
population of poor, the probability is much greater that poor
persons will live in a high pollution area. One need not be poor,
or black, or live in a low rent apartment, or be low on the
occupation ladder to call a polluted area home. However, if a
person falls into one or more of those categories, the chance of
living in such an area increases.
The second
set of maps (Figs. 6-7 to 6-10) compare hydrocarbons and the same
four socioeconomic characteristics and show the same basic
relationships. This is not surprising since CO and HC come from the
same sources in the same way at the same time. The HC-poverty map
(Fig. 6-7) shows an even closer association between pollutant and
characteristic than did the