Environmental Data Analysis BC ENV 3017

Atmospheric Particulates

aerosol = a colloid in which small solid or liquid particles are suspended in a gas
colloid = a mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance
Total Suspended Particulates (TSP), partical size 0.01 - 10mm
PM10 = mass of particulate matter <= 10mm;

increased tightness of modern buildings & windows
molds, dandruffs (cockroach, rat, pet, human), rat & mice feces, pet hair, pollen

the NRC estimates that each year about 64,000 people die prematurely from cardiopulmonary causes linked to particulate air pollution
Premature mortality due to particulate Air pollution in New York (Tab)
current EPA standards: (NAAQS)

PM2.5: annual mean concentrations < 15 µg/m³ , and 24-hour average concentrations < 65 µg/m³
PM10: annual mean concentrations < 50 µg/m³ , and 24-hour average concentrations < 150 µg/m³ (99 percentile form)
these standards will not take immediate effect, there is an implementation timetable for these standards

idealized particle distributions. By size, numeric peak size range < surface area peak size range < total volume peak size range
particles >= 10mm settle from the atmosphere by sedimentation
particles > 0.01 and < 1mm are affected by coagulation (gather together) and condensation
composition of particles reflect their source; i.e. crustal material (dust from rocks) vs. acid aerosols and metals from energy use
anthropogenic sources vary but are usually dominated by fossil fuels (Fig)

burning fossil fuel is the source of most of the organics, most of the sulphate (SO₄) via SO₂ oxidation, most of NO_x , certain metals

there are also natural sources of sulfate, such as volcanoes, DMS (dimethyl sufide) from oceans and estuaries

worst offenders are the small inefficient apartment building incinerators => black cloud of smoke
modern high tech incinerators can be built with very low particulate outputs

low pollution expected during passage of cold fronts, low pressure systems, and during the initial stages of a typical high pressure system, winds from NW or NE
moderate pollution expected on 2nd or 3rd day into new air mass after SW or W air flow established
high pollution expected on backside of a high pressure system (SW or W winds)
very high pollution, same as above but generally associated with slow moving systems

degree days (heating) for a month are defined as the sum of (65F - T) for the days of one month; the mixing height during the winter is larger than during the summer

weekly cycle (fig)
diurnal variation of aerosol concentration, traffic and power production in New York City (Fig)