Smoke filled the air at the Burnside Bridge in downtown Portland last night as marijuana smokers lit their celebratory joints, marking Oregon’s legalization of recreational use.

Oregon’s marijuana supporters have been waiting for this moment since last November, when voters backed Measure 91, a law that allows for recreational use, Reuters reported.

The legislation will also allow for shops to sell marijuana by next year. In the meantime, the state senate passed a bill called SB 460, which was approved in the Senate. This bill would allow recreational marijuana users 21 and older to buy their products from licensed medical marijuana dispensaries beginning October 1, according to the Statesman Journal.

Oregon is one of four states, in addition to the District of Columbia, that has legalized recreational marijuana. So far, 19 states and D.C. have decriminalized the possession of small amounts of marijuana for personal use while 23 states have legalized its use for medical purposes, The Huffington Post reported.

The legislation is one of many steps that show how rapidly states have been warming up to marijuana legalization. Why the sudden shift?

Over the past few years, an increasing number of arguments have been made that legalization can benefit lawmakers, politicians, and consumers alike.

The economic argument, in particular, has been a potent one. It is estimated that a taxed and regulated marijuana industry could reel in approximately $10 billion for the government in upcoming years, VICE News noted. "You're starting to see not just liberal Democrats, but also some very conservative Republicans recognize [prohibition] doesn't make sense, including sort of the libertarian wing of the Republican Party," Obama said.

"They see the money and how costly it is to incarcerate. So, we may actually be able to make some progress on the decriminalization side."

But it’s not just the potential financial gains that have made lawmakers reconsider prohibitions on marijuana consumption. While many states still strongly oppose the decriminalization and legalization of its use, public opinion seems to be moving in the opposite direction.

According to a survey led by the Pew Research Center in April, 53 percent of those polled said they favor the legal use of marijuana, while 44 percent said they are opposed. In 2006, only 32 percent supported marijuana legalization, while nearly twice as many were opposed.

Of those who said they were opposed to legalization in the 2015 survey, many said that they see marijuana as a dangerous drug, one that inflicts damage on people and society more generally. Others also noted the dangers of its potential abuse and addiction.

But supporters of legalization say there is growing evidence that proves otherwise. In 2014, the Center on Juvenile and Criminal Justice carried out an analysis that compared five states that implemented major marijuana reforms, either through legalization or decriminalization, over the last five years.

They found that all five states experienced substantial declines in marijuana possession arrests. They also discovered that marijuana decriminalization in California hasn’t led to harmful consequences for teenagers. Instead, teenagers showed improvements in all risk areas, such as increased crime, drug overdose, driving under the influence, or school dropout, after reforms were made.

There are also medical professionals who have been working to change the face of the marijuana industry.

Sanjay Gupta has been a notable trailblazer in the medical marijuana field. In April, he said he’s hopeful that others will soon join the legalization movement. “I see the revolution in the eyes of sterling scientists, previously reluctant to dip a toe into this heavily stigmatized world, who are diving in head first.”

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Efforts to eradicate the "stoner stigma" have also been popping up outside the world of medical marijuana. Cannabrand, a cannabis-branding agency that’s dedicated to the marketing of cannabis products and services, has been working to change the face of recreational marijuana consumption since 2014.

“We’re weeding out the stoners,” co-founder Olivia Mannix told The New York Times. “We want to show the world that normal, professional, successful people consume cannabis,” she said.