Table 1.

Studies of the effect of different air pollutants on birch pollen grains.

Birch species	Pollutant(s) studied	Concentration range	Duration of exposure	Germination or viability	Total proteins	Protein profiles	IgE recognition	Reference
B. pendula	NO2	34/67 ppb	6/48 h	↘	↘	—	↗	[153]
Birch allergen	NO2	—	—	—	—	—	↗	[154]
B. verrucosa	NO	1–5%	48 h	—	↘	Numerous modifications	—	[155]
B. alba	NO2	1–400 ppm	Hours to days	—	—	—	—	[134]
B. pendula	O3	61–192 ppb	6/12 h	↘	↘	—	—	[156]
B. papyrifera	O3	Ambient/ambient × 1.5	9 years	↘	—	—	—	[87]
B. pendula	CO	10–31 ppm	6/12 h	↘	↘	—	—	[156]
B. papyrifera	CO2	360–560 ppm	9 years	↗	—	—	—	[87]
B. verrucosa	CO	0.01–5%	48 h	—	↘	Numerous modifications	—	[143, 155]
B. verrucosa	CO	100%	2 h	—	—	—	—	[69]
B. pendula	Comparison rural/urban	—	—	—	—	↗ Bet v 1	—	[172]
B. pendula	SO2	130–540 ppb	6/12 h	↘	↘	—	—	[156]
Betula sp.	NO2/O3 /urbanization index	—	—	—	—	↗ (Bet v 1 for O3)	↗ (for O3)	[98]
Betula sp.	Comparison rural/urban	—	—	—	—	Differences in spot intensities	—	[96]
B. papyrifera	CO2 + O3	CO2: 360–560 ppm O3: Ambient/ambient × 1.5	9 years	=	—	—	—	[87]
Birch (proteins)	Urban air or NO2 + O3	100 ppb	5/50 h	—	—	Nitration of Bet v 1	—	[173, 174]
B. pendula,  B. pubescens	Sulfur and heavy metals	—	—	—	=	—	=	[55]
B. verrucosa	Comparison rural/urban	—	—	↘	—	—	—	[80]
B. verrucosa	SO2	1%	2 h	—	—	—	—	[69]
Betula sp.	Urban with traffic	Exposed to urban pollution	24/72 h	—	—	—	—	[66]