article_snippet.sent: But for millions, the  first tentative steps towards summer brings impending misery as a dreaded cloud of invisible pollen descends.
article_snippet.sent: She said: 'If we get prolonged periods of warm, dry weather with intervals of some wet weather between, which helps the grass to keep growing, we will experience a lot of high grass pollen counts. '
article_snippet.sent: Grass is the main culprit pollen for hayfever in the UK. '
article_snippet.sent: She added: 'In addition, the good weather typically brings increases in air pollution, which can make symptoms worse, and again lead High and very high pollen counts to occur in people who have been symptom free before.'
article_snippet.sent: In addition, She said pollen is becoming more potent, and greater numbers of plants giving off the allergens is also contributing to a rising number of sufferers.
article_snippet.sent: She added: 'There is substantial evidence from pollen monitoring records and from vegetation surveys to show that the timing of some of the pollen seasons has been changing in the UK and across Europe over the last few decades.
article_snippet.sent: In addition there has been a trend to longer pollen seasons and increasing pollen loads of some types. '
article_snippet.sent: Globally, average surface temperatures have increased by about 0.7°C over the past 100 years, leading to earlier plant growth in many regions. '
article_snippet.sent: The trend towards warming has been more pronounced in winter months, resulting in more changes in the timing of spring pollen seasons than those of summer and autumn.'
article_snippet.sent: The allergy is a seasonal one, triggered by a range of different pollens ranging from tree to grass, weeds to fungal spores.
article_snippet.sent: As summers become warmer more photochemical smogs will occur on dry days resulting in an increased frequency of days with high concentrations of ozone, NOx and other pollutants that will make symptoms worse, and that will make people more susceptible to allergens,' she said. '
article_snippet.sent: Due to climate change in the future, plant growth may be influenced in a way that more, new and altered pollens are produced, which may affect humans.'
article_snippet.sent: Dr Emberlin, speaking on behalf of Opticrom Hayfever Eye Drops, warned the season is expected to start suddenly with pollen counts surging from almost nothing to very high in a matter of days.
article_snippet.sent: It is very important to know the seasons, when it is likely to peak and the days when pollen levels will be particularly high. '
article_snippet.sent: Dr Emberlin said pollen counts can suddenly surge if conditions are right. '
article_snippet.sent: A warm day with a slight breeze can signal the perfect conditions for spores to infest the air, causing pollen levels to surge,' Dr Emberlin warned.
highlights_snippet.sent: Experts told MailOnline warmer weather can result in very high pollen counts which trigger symptoms in new sufferers .
  
highlights_snippet.sent: High temperatures also increase air pollution, which worsen symptoms .