The health effects of this type of air pollution have become of increasing concern in recent years, as numerous studies have shown an association between particle concentrations and rates of mortality and illness, usually involving the lungs or heart. In Saint John, a detailed study has been underway since 1992 in which both enhanced environmental monitoring data have been obtained, together with health information gathered at the Saint John Regional Hospital.

NB ENV has been co-operating with federal health and atmospheric scientists in this study. Additional financial support was provided by NB ENV, NB Power and Irving Oil Limited for work carried out in 1995. The study is known as the Canadian Acid Aerosol Measurement program (CAAMP).

The monitoring component of the study has concentrated on the collection of enhanced particle data, especially chemistry. Monitored locations include Forest Hills, Point Lepreau, downtown Saint John (Provincial Building), the Kennebecasis Valley Junior High School, and Norton ?check Quispam?. These locations were chosen to provide information which would allow comparison of rural, urban and suburban locations, and also show how particle chemistry changes as airmasses move out of the city up the Kennebecasis Valley.

For comparison purposes across eastern Canada, special acid aerosol measurements were also obtained at six other sites: Kejimkujik, Nova Scotia, Montreal and Sutton, Quebec, and Toronto, Egbert, and Windsor in Ontario.

The measurements made as part of the CAAMP program include daily PM10 and PM2.5 particle concentrations, plus details of the chemistry of fine particles including acidity and trace element concentrations. This information helps identify the potential sources of particles in the different size ranges and may help understand what chemical properties of fine particles cause effects on human health. Data were also gathered on the concentrations of pollen and spores in the air, as these are aslo suspected as potential causes of some respiratory problems.

The CAAMP program began in summer 1992 and became more developed in Saint John in 1993 and 1994, when additional monitoring sites were set up. Some of the basic results obtained so far are summarized in the following paragraphs. Complete, detailed results are available in a series of technical publications. Readers who are interested in more complete details should refer to the contact list.

Aerosol acidity was found to be highest at Maritime sites and lowest at urban sites such as Montreal, Windsor and Toronto. Within the Maritime region, particulate in Saint John has a greater sulphate content and higher acidity than that seen at Kejimkujik, Nova Scotia, which is remote from any local sources of sulphur dioxide. In fact, aerosol acidity at Saint John was the highest in the CAAMP network and was greater than rural background by 120-200%. SO2 is believed to increase the sulphate content of airborne particles found in the Saint John region.

The high particle acidity seen in Saint John is thought to be due in part to reduced neutralisation of the acidity, as airmasses affecting the Maritime region often travel across the ocean or over unpopulated, forested areas. Most neutralisation is due to ammonia, and ammonia concentrations are low in the Maritimes and over the ocean. As neutralisation increases with distance of air movement, the conclusion was that the high acidity was due to pollution sources within the city.

There were indications that high acidity was linked with coastal fog occurrence. This does not necessarily mean that fog somehow causes high particle acidity, although it may play a role.

High acidity is typically recorded in recurring spells, each of a few day's duration. These episodes affect the entire southern Maritimes, as data for Saint John and Kejimkujik often show elevated acidity at the same time. This means that the broad scale weather patterns which affect the whole region have a significant influence on particle chemistry. This is due to a variety of reasons including the movement of polluted air into the region and the occurrence of stable weather conditions which favour pollutant build-up. These are the same conditions that lead to high ozone levels.

In 1994, when 3 additional sites were added to the aerosol monitoring program in the Saint John region, the summer was close to the long term average in terms of air pollution. Pollen and spores were sampled at a site in Quispamsis in 1994. Preliminary results showed little association between pollen and spore counts and respiratory health symptoms.

The 1994 data showed that fine particles are most acidic in Saint John east of the downtown area, and at Quispamsis. Concentrations of fine particles, and the level of acidity of these particles, were greater in Saint John and Quispamsis compared to Point Lepreau, 40 km to the southwest of the city.

In 1995, more detailed measurements of ultrafine particles were examined using a multistage impactor sampling device. Some researchers believe that PM1.0, or even smaller sizes, are the most critical as far as human health effects are concerned. The multistage impactor provides information on particle concentrations in multiple size ranges, down to as small as 0.01 micron diameter.