Abstract
Since 1953, there has been a significant increase in the number of hours (May to October) of reported haze, smoke and/or dust at synoptic observing stations in the Atlantic Provinces and Eastern Quebec. Because the increase is associated mainly with south to southwest winds, and because there has in fact been a decrease in particulate emissions in eastern North America during this period, the suggestion is made that the increase in haziness is due to increasing photochemical activity, resulting from greater emissions of gases such as SO2 and NOx from sources along the United States eastern seaboard.