date	date (YYYY-MM-DD)
dow	day of the week (indicator)
death 	count of deaths from all causes excluding external causes
pm10tmean	PM10 detrended
o3tmean	ozone detrended
so2tmean	sulphur dioxide detrended
no2tmean	nitrogen dioxide detrended
cotmean	carbon monoxide detrended
tmpd	average of maximum and minimum temperature (deg. F)
dptp	dew point temperature (deg. F)
rhum	relative humidity