External Factors for Smog Problem
In addition to local burning and natural forest fire, another contributing cause
of smog crisis in Chiang Mai province comes from outside the country. An image
taken by NOAA satellite on March 16, 2010, just before the rate of fine particulate
matter (PM 10) reached the highest level, show many hotspots in the Northern region
of Thailand as well as in the neighboring countries, i.e., 383 spots in Laos, 499 spots
in Cambodia, and 155 spots in Vietnam. Thailand has the second most hotspot in the
region, mostly in the Northern part of the country7 On that particular day, Mae Chaem
had on 35 spots on the map, from 49 spots of Chiang Mai. Even though Chiang Mai
had a very high rates of hotspots, it ranks third in the country after Mae Hong Son and
Nan as shown in Table 3.