depicted in Smog City are estimated by simulating the air quality
over Sacramento, California using a computerized model of the
model creates an imaginary box over the area to represent the
atmosphere above Sacramento. Air quality conditions in the box
are simulated to account for both human influences and natural
factors that affect ozone formation.
simulation represents one day. In the morning, the box has healthy
air quality conditions. As each hour of the day passes, emissions
from human activities, such as industry, cars, and trucks, and from
natural sources like trees and plants, are injected into Smog City's
atmosphere. Emissions take into account variations in human activity,
such as morning rush-hour traffic. Emissions are then subjected
to movement and mixing, which are influenced by weather characteristics
such as wind speed, sunlight, and temperature.
model simulations were
run to develop Smog City's relationships between
weather, population, emissions levels, and ozone.
The computer model takes these meteorological effects
into account in determining the rate of chemical reactions that
cause ozone levels to rise or fall. The model uses 85 chemical reactions
and 30 different chemical compounds to simulate ozone formation.